MXPA06001872A - Method and apparatus for destruction of liquid toxic wastes and generation of a reducing gas. - Google Patents

Abstract

The invention relates to a method and system for destroying liquid toxic materials for example polychlorinated biphenyls, and producing a reducing gas. In a preferred embodiment, harmful intermediates are not generated when the toxic materials are destroyed due to the reducing atmosphere produced by partial combustion with a molecular-oxygen-containing gas and steam. Liquid materials containing high concentrations of PCB's are mixed with non-toxic hydrocarbons for sustaining an autothermic reaction. The efficiency of the PCB's destruction process exceeds the required environmental regulations and produces a useful reducing gas which can be utilized as a synthesis gas in chemical processes or as a fuel for heat and/or power production.

Description

METHOD AND APPARATUS FOR THE DESTRUCTION OF TOXIC LIQUID WASTE AND THE GENERATION OF A REDUCING GAS FIELD OF THE INVENTION The present invention relates to the handling and destruction of toxic waste. More particularly, the present invention relates to the transformation of toxic waste materials, such as halogenated organic compounds with liquids and solids into a non-toxic reducing gas. The non-toxic reducing gas can be used as synthesis gas, as a fuel or as a chemical reducing agent in, for example, the chemical reduction of iron oxides to metallic iron. The documents cited in this text, and all documents cited or referred to in the documents cited in this text, are incorporated herein by reference. The documents incorporated by reference in this text or any content thereof could be used in the practice of this invention. Documents incorporated by reference in this text are not allowed as relevant prior art. Additionally, the authors or inventors referred to in the documents incorporated by reference in this text should not be considered as "other" or "other" with respect to the inventors of the present invention and vice versa, especially when one or more authors or inventors cited in The documents incorporated by reference in this text are an inventor or inventors named in the present group of inventors.

BACKGROUND OF THE INVENTION Hazardous and environmentally harmful substances, such as polychlorinated biphenyls (PCBs) and their destruction in a safe manner, are a major concern in the industrialized world. PCBs are one of the best known compounds referred to in the industry as POP's (persistent organic pollutants). These contaminants also include pesticides such as DDT, and CFCs (chlorofluorocarbons), halogenated benzenes, halogenated phenols, halogenated alkanes, halogenated cycloacanes, halogenated dixins and halogenated dibenzofurans. A number of methods have been proposed to dispose of and destroy toxic waste materials. See for example a report titled "Destruction Technologies for Polychlorinated Biphenyls (PCBs)" by M.S.M. Muheebur Rahuman, Luigi Pistone, Ferruccio Trifiro and Stanislav Miertus (2002) (incorporated herein by reference). Some of the methods described in this report can be summarized as follows: (1) high temperature incineration with oxygen; (2) incineration in cement kilns; (3) supercritical oxidation; (4) electrochemical oxidation; (5) solvated electron technology; (6) chemical reduction reactions; (7) dehalogenation processes, and other complex technologies. Oxygen incineration is typically carried out in rotary kilns at temperatures of about 870 ° C to 1200 ° C. Destruction efficiencies of up to 99.9999% can be achieved. In some places liquid wastes are incinerated with concentrations of PCBs above 50 ppm if such incineration meets a residence time of at least 2 seconds at 1200 ° C and 3% excess oxygen in the flue gases. One of the problems associated with incineration is the control of atmospheric oxygen in order to avoid the formation of dioxins and benzofurans that are also toxic. The treatment of the waste in the cement kilns also involves some type of incineration. Because they operate at temperatures above 1400 ° C and internal conditions are highly alkaline, cement kilns decompose chlorinated organic waste. The amount of waste, however, is limited to a small fraction of the fuel requirements of the oven and no liquid or solid waste is generated, since all the waste leaves the oven attached to the product. When properly operated, the destruction of chlorinated compounds can reach 99.00%, without affecting the quality of the exhaust gas. However, not all cement kilns qualify for this use and not all companies want to handle waste products in their normal production operations. Chemical reduction technologies involve the gas phase chemical reduction of organic compounds with hydrogen at temperatures above about 850 ° C. This process has been applied for the destruction of a variety of organic compounds such as chlorophenols, dioxins, chlorobenzenes, pesticides, herbicides and insecticides. These compounds are converted to methane. Approximately 40% of the methane produced is converted to hydrogen and CO by the gaseous conversion reaction of water, and the remaining methane is converted to hydrogen in a catalytic steam reformer that combines with the waste oil so that the oxidation reaction It is done in a reducing atmosphere without oxygen. In this way, it is said that the possibility of formation of dioxins and furans is eliminated. U.S. Patent No. 3,140,155 to J.A. Culi et al. it is related to a process and a furnace for the recovery of hydrogen chloride from chlorinated waste such as hexachlorocyclopentadiene, and trichlorobenzenes. Although the Culi process involves the reaction of the chlorinated compounds with air / oxygen and steam, the gases produced from that reaction are not intended to comprise significant proportions of hydrogen and CO but only to obtain as much hydrogen chloride as possible. U.S. Patent No. 3,305,309 to R. G. Woodland et al. It relates to a process and apparatus for converting halogenated organic materials to gaseous products comprising carbon dioxide and a hydrogen halide. The halogenated organic compounds are reacted with air or oxygen and steam in a tubular burner where a fine mixture of the vapor with the halogenated organic material is made, steam passing under pressure through a restrictive zone and an expansion zone. The halogenated material is introduced into the expansion zone and comes into contact with the vapor. The mixture is atomized by passing it through a restrictive zone to an expansion zone where the mixture is combined with oxygen or air. Preferably, the atomized mixture is wrapped in the gaseous medium as it is injected into the combustion zone. U.S. Patent Nos. 4,074,981 and 4,468,376 describe a process for destroying a halogenated organic material by means of the partial oxidation of said organic material together with a hydrocarbon material and a nitrogen compound with a gas containing free oxygen. Partial oxidation produces a synthesis gas that contains hydrogen, carbon monoxide, carbon dioxide, hydrogen cyanide, hydrogen halide, and ammonia. The synthesis gas produced is contacted with water containing additional ammonia to neutralize the hydrogen halide.

U.S. Patent No. 4,631,183 to Lalancette et al. is related to a process for the destruction of toxic halogenated organic substances which comprises treating in a reaction chamber, under a reducing atmosphere and at high temperatures in the range of 1000 ° C to 1600 ° C, a mixture of a toxic halogenated substance, carbon and a carbonate or bicarbonate of an alkali metal, so that vapors of the alkali metal are generated in situ causing the total degradation of the toxic substance to non-toxic compounds. During the process, carbon monoxide is generated and oxidized to carbon dioxide in a separate combustion chamber. The gases resulting from this process are completely oxidized, but a usable gas containing hydrogen and carbon monoxide is not produced. German patent DE 41 09 231 A1 describes a process for transforming waste halogenated hydrocarbons to produce a gas containing hydrogen and carbon monoxide by partial oxidation with oxygen in a flame reaction. The hydrocarbon is combined with oxygen under pressure. The gases produced are cooled and then passed through a catalytic converter to convert the gases to a desired final composition by means of the known water gas conversion reaction. The hot gases are cooled with water containing an alkaline additive. The process of this patent however has several disadvantages, e.g. the halogenated hydrocarbon reacts with oxygen only without the presence of a temperature moderator, therefore, the flame temperature is extremely high requiring a highly specialized refractory coating. The carbon dioxide content in the gases produced by the partial combustion is relatively high, and an additional reactor is required to convert a portion of the carbon monoxide to hydrogen. The water necessary for the gaseous conversion reaction of water is added to the gas by evaporation of the cooling water. This method of adding water is not efficient because it depends on the saturation conditions of the gases. U.S. Patent 4,402,274 relates to a process of partial oxidation of the toxic matl followed by a cooling of the reaction products. U.S. Patent No. 4,140,066 to Rathjen et al. describes a process for the thermal decomposition of polychlorinated organic compounds such as polychlorinated phenyls or biphenyls comprising heat treating said compounds in a flame inside a high turbulence combustion chamber in a pulsating spiral flow at a temperature of at least 850 ° C with a residence time of at least 0.1 seconds in the presence of an excess of at least about 5% by weight of oxygen based on the coal to be burned, with the PCB present in the feed fuel in a concentration from about 0.1 to 30% by weight. The process of this patent is a complete combustion process and does not produce a reducing gas as a result of said oxidation reaction. Patents Nos. 4,819,571 and 5,050,511 to Hallet describe a system for the destruction of organic waste matl (PCBs and similar organic waste matls) which comprises subjecting the waste matl to a reduction with hydrogen at a temperature higher than 600 ° C with an indirect heating of the combustion chamber, and subsequently oxidizing the resulting hot reaction mixture at a temperature higher than 1000 ° C. The system includes a reduction vessel and an adjacent combustor for the oxidation reaction. The process of this patent comprises a two-stage method which requires at least two high-temperature reactors and a hydrogen generator. Patents Nos. 5,449,854 and 5,609,104 to Yap relate to a method and an incinerator for incinerating halogenated organic compounds. The process comprises two stages, one where an auxiliary fuel, for example natural gas, is partially combusted to generate hydrogen and a second stage where the gases produced in the first stage are burned completely with additional oxygen. This two-step process is said to minimize the formation of halogenated furans and dioxins. The Yap process is complex and is aimed at incinerating the halogenated compounds, not at producing a usable gas. U.S. Patent Nos. 4,851, 600, of England 1, 350,727 and of Germany DE 41 25 518 also relate to processes for the destruction of halogenated organic materials where said materials burn completely in multiple stages of combustion or in the presence of metals that capture chlorine. U.S. Patents 4,869,731, 5,074,890 and 4,950,309 describe a process for the thermal decomposition of refractory organic substances. The toxic substances are brought into contact with an oxidizing medium and vapor at a temperature in the range of 2500 ° F (1371 ° C) to 3200 ° F (1760 ° C) for a period of 5 to 500 milliseconds in a reaction chamber . The process of this patent requires extremely high temperatures and the reaction time is very short. Therefore, the materials are also in contact with incandescent or refractory coal. U.S. Patent Publication No. 2002/0098133 A1 refers to processes for the conversion of halogenated materials into one or more useful products. These products may be an acid and / or a synthesis gas usable. U.S. Patents 2,928,460, 3,462,250,3,545,926, 3,743,606 and 3,874,592 describe burners for the partial oxidation of hydrocarbons. These patents provide designs for achieving the atomization of liquid hydrocarbons by combining a gaseous stream of an oxidant with a separate stream of the hydrocarbon at the outlet end of the burner. These burner designs, however, rely more on the atomization of the liquid than on favoring a dispersed flow pattern of the liquid and gas phases, and have the disadvantage of not producing an efficient, non-dispersed coherent flame. Currently, large amounts of contaminated materials, such as those containing PCBs, and other toxic waste are stored at a high cost in many parts of the world awaiting their destruction. This implies important environmental risks. Prior art methods for destroying contaminated materials, however, have many disadvantages. For example, prior art processes do not completely destroy the PCBs. Additionally, the operating cost of these processes is high; typically without taking into account the economic benefits and the use of complex and expensive equipment and require multi-stage reactions. Additionally, harmful intermediates can be produced. There is therefore a need in the art for the destruction of toxic materials by means of partial oxidation and the generation of a reducing gas in a single reaction vessel. There is also a need for an efficient and low-cost method to destroy such toxic materials without producing harmful or unwanted intermediates.

OBJECTS OF THE INVENTION It is therefore an object of the invention to provide an efficient and low-cost process and equipment for the destruction of toxic waste materials. It is another object of the invention to provide a method and apparatus for producing a reducing gas which can be used as a fuel or chemical reducing agent for example in the reduction of iron oxides. It is still another object of the invention to destroy toxic wastes, such as PCBs, without producing harmful intermediates, such as dioxins.

Other objects will be indicated here later or will be evident for those readers who are experts in the art. According to one embodiment of the present invention, therefore, a method is provided for the destruction of a toxic material without producing harmful intermediates, which has the steps of destroying said toxic material, by means of a partial oxidation reaction in a heated reaction vessel, contacting a liquid hydrocarbon material comprising said toxic material with steam and an oxygen source, and producing with said reaction a reducing gas comprising hydrogen and carbon monoxide. In accordance with another embodiment of the present invention, there is provided a system for the destruction of toxic waste materials and for the production of a reducing gas comprising hydrogen and carbon monoxide, wherein said system has a partial combustion chamber; a burner where oxygen, steam and said toxic materials react producing a flame of gases at high temperature within said partial combustion chamber; and means for cooling said flame gases. In this description, "comprises", "comprise" and similar terms may mean "include", "comprise" and similar words.

BRIEF DESCRIPTION OF THE DRAWINGS In this specification and the accompanying drawings, some preferred embodiments of the invention are shown and described, and various alternatives and modifications to it are suggested. It will be understood that these are not intended to be exhaustive and that other changes and modifications may be made within the scope of the invention. The suggestions contained herein have been selected and included for purposes of illustration so that those skilled in the art can better understand the invention and the principles thereof and are thus empowered to modify it in a variety of ways, each as best suited to the conditions of a particular use.

In the detailed description that follows, reference will be made to the accompanying drawings in which: Figure 1 is a schematic diagram of the process for processing toxic waste hydrocarbons. Figure 2 is a schematic diagram of a burner used to partially burn the toxic waste hydrocarbons.

DETAILED DESCRIPTION OF PREFERRED AND ILLUSTRATIVE MODALITIES OF THE INVENTION Typically, the destruction of toxic waste follows a process in which noxious intermediates are produced. The present invention destroys toxic materials, such as PCBs, with the advantage of not producing these harmful intermediates, such as dioxins or furans. For example, it has been unexpectedly discovered that by maintaining the refractory temperature above that of the fed materials, the efficiency of the partial combustion reaction is increased. Additionally, by limiting the oxygen supply to a smaller proportion than stoichiometrically necessary for complete combustion, said toxic intermediate substances are not generated. Instead, one of the final products of the present invention is HCl, which can be easily neutralized with NaOH. Typically, the refractory is maintained at a temperature above about 650 ° C, preferably above about 750 ° C, depending on the type of material being gassed. Additionally, fuel is saved by heating the refractory. In fact, the prior art uses additional fuel to maintain a flame that heats the refractory, which is avoided with the present invention. The present invention, for example, uses water vapor as a reducing source, regulating the oxygen ratio and monitoring the temperature, achieving an efficiency in the destruction of toxic waste of 99.9999%. Also, the use of water vapor is less expensive than the use of hydrocarbon fuels, and water vapor can be a byproduct of a separate concurrent reaction. In a preferred embodiment, the present invention carries out the combustion reaction by mixing water vapor and oxygen, the mixture of which surrounds a jet of liquid containing PCBs in a tube with such dimensions that the conditions for a dispersed flow of two are met. phases within said tube, in such a way that a stable, coherent, narrow and controlled flame is produced inside a combustion chamber surrounding the outlet end of said tube. The present invention can be applied to virtually any hydrocarbon having any contaminant, without being limited to, BPC's, dioxins, pesticides and solvents in any concentration. Typical hydrocarbons include oils from electrical equipment contaminated with PCBs, waste pesticides and other oils and waste hydrocarbons from the petrochemical industry. The present invention also avoids the need for a catalytic converter that is ordinarily used to generate a process reducing gas from hydrocarbons. The present invention provides, for example, a method for the destruction of a toxic material contained in a liquid hydrocarbon without producing noxious intermediates. The steps of the method include mixing said liquid hydrocarbon comprising said toxic material with steam and a gas containing molecular oxygen in a flow channel and regulating the flow rates of said liquid hydrocarbon and said water vapor and oxygen containing gas of such so that the speed of the mixture of liquid and gas at the outlet of said flow channel is greater than approximately 40m / s; introducing said mixture of liquid and gas into a reaction vessel having a refractory lining at a temperature greater than about 650 ° C; maintain for at least 2 seconds the reducing gases produced at high temperature comprising molecular hydrogen within said reaction vessel; maintaining a temperature above about 1000 ° C at the outlet of said reaction vessel; and to cool and wash the gaseous products with water. As a result of this method, a reducing gas comprising hydrogen and carbon monoxide substantially free of said toxic material as a result of partial combustion said liquid hydrocarbon is produced. The toxic material may comprise one or more of the substances: polychlorinated biphenyls, pesticides, chlorofluorocarbons, halogenated benzenes, halogenated phenols, halogenated alkanes, halogenated cycloalkanes, halogenated dioxins or halogenated dibenzofurans or combinations thereof. In a preferred embodiment, the liquid hydrocarbon is oil. Preferably, the speed of the mixture of liquid and gas at the outlet of said flow channel is greater than about 50 m / s. In addition, the refractory lining of said reaction vessel is preferably maintained at a temperature greater than about 750 ° C. The liquid hydrocarbon, in turn, preferably contains less than about 50% by weight of polychlorinated biphenyls. In one embodiment, the liquid hydrocarbon containing polychlorinated biphenyls is mixed with hydrocarbons that do not contain polychlorinated biphenyls before introducing said hydrocarbon into said reaction vessel, to ensure partial auto-thermal combustion of the hydrocarbon mixture. Preferably, the hydrocarbon mixture has less than about 50% by weight of polychlorinated biphenyls before being introduced into said reaction vessel. The hydrocarbon mixture may have less than about 10% by weight of polychlorinated biphenyls before being introduced into said reaction vessel. Additionally, the water used for the cooling of said gas is typically mixed with an alkaline compound to neutralize the acidity derived from the absorption of chlorine in the water. Also, the water used for cooling said gas preferably receives a treatment for concentrating and recovering HCI derived from the absorption of chlorine by said water. The present invention also provides a system for the destruction of liquids containing toxic materials and for producing a reducing gas comprising hydrogen and carbon monoxide. In a preferred embodiment, the system includes a partial combustion chamber, said partial combustion chamber having a refractory lining adapted to be heated and maintained at high temperature by the produced flame gases and said chamber having an inlet and an outlet: a channel of flow having a length to diameter ratio of at least about 4, and where an oxygen stream, a stream of water vapor and a stream of the liquid containing said toxic materials are intimately mixed; said flow channel being in communication with said inlet of the combustion chamber: and means for cooling said gas communicated with said outlet of the combustion chamber to cool said flame gases. Preferably, the length-to-diameter ratio of said flow channel is at least about 30. A preferred embodiment of the invention is described herein with reference to Figure 1, where the numeral 10 designates in general form a partial combustion reactor that it comprises a burner 12 and a wall covered with refractory14. A waste liquid hydrocarbon stream 16 is combined with an oxygen-containing gas 18 in said burner, it can be pure oxygen, air or air enriched with oxygen in various proportions, depending on the desired quality of the product gas. Water vapor 20 supplied from a suitable source is injected 23, or optionally, produced in a boiler 32 and fed through the tube 21, to the burner 12 so that the hydrocarbon 16, the oxygen 18 and the water vapor 20 react and produce a high temperature flame 22 within the reaction space 24 of the reactor 10. The reaction space 24 is designed in accordance with the feed rate of the reagents such that the residence time of the flame gases exceeds about 2 seconds, preferably about 3 seconds, at a higher temperature at approximately 1600 ° C. The high-temperature flame reaction destroys the complex molecules of the halogenated compounds, under a reducing atmosphere. The oxygen-containing gas is fed to the burner 12 in an amount less than the stoichiometrically necessary amount to complete the combustion of the hydrocarbons. In a preferred embodiment of the invention, the gases produced in the burner 12 exit the reactor 10 through the tube 26 and are cooled to a temperature below about 300 ° C by contact with cooling water 28 from a suitable source 29 in a cooling hole 30. The cooled gases and water subsequently pass through a heat exchanger 32 where water vapor is produced from water 34 from a source 36, and is fed to burner 12 by means of tubes 20 and 21. The reducing gas 38 is treated in a scrubber 40 where it is brought into contact with water 42 from a source 44. The hydrochloric acid formed by the combination of the chlorine atoms of the polychlorinated biphenyls with hydrogen produced by the partial combustion of the hydrocarbons, is absorbed by water and is extracted in solution with water 48. This water with acid can be treated additionally to concentrate the hydrochloric acid for sale or can be treated on sodium hydroxide for neutralization. Draft gas 46 produced from contaminated hydrocarbons can be used as a synthesis gas, as a chemical reagent in other chemical processes or as a fuel for the production of water vapor or electricity. Liquid hydrocarbons contaminated with PCBs are contained mainly in electrical equipment, e.g. transformers, capacitors and similar equipment, in a variety of concentrations. The concentration of PCBs in the refrigerating oils of electrical equipment can be less than 50 ppm (parts per million) and even almost pure PCBs. One of the main properties of PCBs is their chemical stability and therefore they do not react easily with oxygen due to the strength of their molecular chemical bonds with chlorine and its low calorific value. Materials that have high concentrations of PCBs may not be able to sustain a stable reaction with oxygen, and therefore it is recommended to mix them with other uncontaminated hydrocarbons, in order to reduce their concentration to levels below approximately 600,000 ppm (60% in weight), and preferably below about 300,000 ppm and more preferably below about 110,000 ppm. With reference to Figure 1, the contaminated hydrocarbons are transferred from a storage tank 50 by means of a tube 52 provided with a valve 54 to a mixing tank 56. The mixing tank 56 is provided with stirring means 58 to obtain a homogeneous composition of the materials fed to the reactor 10, and of a load cells 60. The hydrocarbons contaminated with BPC's are transferred from the storage tank 62 by means of the tube 64 provided with a valve 66 to the mixing tank 56. The signals from the load cells 60 in the controller 68 to prepare batches of hydrocarbons with predetermined concentration levels of BPC's. After mixing, the hydrocarbons are passed to the feed tank 70 through the tube 72 provided with a valve 74. From the feed tank 70 the hydrocarbons are fed to the burner 12 by any of the pumps 76 or 78 through the tube 16 which It has a control valve 80. The proportions of water vapor, oxygen and hydrocarbons are controlled by means of the controller 68 and the control valves 19, 21 and 80, in accordance with the predetermined values of the process parameters comprising the minimum desired temperature and the residence time in the reaction chamber 24 to destroy the PCB molecules, resulting in the complete destruction of the toxic materials. The temperature for the destruction of PCBs at the outlet of reactor 10 is in the range of about 1000 ° C and about 100 ° C. Flame temperatures can reach more than 2000 ° C, but the average temperature of the gases after the endothermic reactions to produce the drafting gas - with a typical composition of approximately 45.6% hydrogen; approximately 34.6% carbon monoxide; approximately 18.9% carbon dioxide; approximately 0.6% methane; approximately 0.4% nitrogen; and traces of other materials - decrease the temperature of the gases to approximately 1000 ° C. This temperature of the gases can be regulated by means of the ratio of water vapor to oxygen and hydrocarbons. The reducing character of the gases inside the reactor 10 prevents the formation of dioxins and furans, thus ensuring a safe operation of the PCB destruction process, unlike the incineration processes where an excess of oxygen favors said formation unless the gases hot ones are cooled immediately and very quickly. The invention also comprises an injection burner or lance to produce a flame consistent with the mixture of contaminated hydrocarbons, water vapor and oxygen and to feed this mixture into the high temperature reaction chamber 24 of reactor 10. Any burner can be used which produce a liquid atomization so that the hydrocarbons are not decomposed by the high temperature of the reaction chamber and form soot thus decreasing the gasification efficiency. In a preferred embodiment, a burner consisting of a tube inside another tube is used to produce a long and coherent flame that favors full contact and mixing of the reactants. With reference to Figure 2, there is provided a burner 1 10 for the partial combustion of the hydrocarbons, useful to ensure the destruction of toxic compounds, with a first inlet 112 and a second inlet 114 and an outlet 116. The burner is also provided of flanges 128 for fixing it to reactor 10 as is known in the art. The liquid hydrocarbon is fed through a first conduit 118 to said first inlet 112 and then injected through the inner tube 120 into the outer tube 110. A mixture of water vapor and a gas containing molecular oxygen is fed through a second conduit 122 to the second inlet 114 and flows together with the liquid hydrocarbon through the outer tube 110. Maintaining the length ratio 124 to diameter 126 of the burner tube 1 0 greater than or equal to 4, preferably in the range of about 30 At about 36, the liquid hydrocarbon and the gaseous mixture of water vapor and oxygen develop a flow pattern known as dispersed flow, as eg a mixture of small drops of liquid dragged by the gas. This intimate contact of the reagents minimizes the formation of soot and increases the efficiency of the gasification process. In order for this dispersion flow pattern to develop, the velocity of the gas phase is very important, therefore, the internal diameter of the tube 110 is selected according to the hydrocarbon feed rate so that the actual gas velocity is about 40 m / s to about 60 m / s, preferably from about 45 m / s to about 55 m / s. Typically, 1 NCM of water vapor / gas with oxygen is required for 1 kg of hydrocarbon. Once the flow velocity of the reactants is defined, the internal diameter and the length of the tube 1 0 are selected. The lance-burner of the present invention for the partial combustion of the hydrocarbons provides an intimate contact of the liquid and the gaseous phases passing through the tube in contrast to the burner structures of the prior art which are based on directing a gas stream which collides with a liquid stream separately. The burner of the invention produces a coherent and compact flame with high reaction efficiency because the speed vector of the mixture is sufficient to project it freely into the reaction chamber, similar to the way a long rifle barrel directs a bullet. The prior art instead directs separate streams of liquid and gas in various directions at the burner outlet to promote the collision of currents with each other and disperse the particles in the reaction space. It has been found that the burner of the present invention can also be used for the gasification of hydrocarbons different from those contaminated with PCB's. For example, the invention can also be applied for the gasification of a solid hydrocarbon mud milled, for example, petroleum coke or coal and for the destruction of other types of toxic materials, for example, insecticides, Freon gases, solvents, chlorofluorocarbons, biocides and hospital waste. The present invention is further described by means of the following illustrative and non-limiting examples which provide a better understanding of the invention and its many advantages.

EXAMPLES The following examples are included herein to illustrate various embodiments in accordance with the present invention. The following examples, however, are in no way intended to limit the present invention.

Example 1 A burner with an inside diameter of ¾ inch was used to gasify three different types of liquid hydrocarbons without toxic materials and produce a usable reducing gas, as follows: Unit Flow velocity Corrida 1 Corrida 2 Corrida 3 Hydrocarbon: (Kg / Hr) 54.0 56.3 52.0 Oxygen: (MCN / Hr) 54.0 34.4 47.2 Vapor water: (MCN / Hr) 35.0 32.7 37.0 The hydrocarbons were treated according to the invention, and a reducing gas was produced in the amount and with the composition (dry base) shown below: Reducing gas: (MCN / Hr) 142.0 104.0 143.2 H2:% vol. 47.90 45.7 46.8 CO:% vol. 30.23 24.1 27.0 C02:% vol. 18.79 24.5 19.9 CH4:% vol. 2.61 5.3 6.0 N2:% vol. 0.47 0.4 0.2 Example 2 Oil contaminated with PCB's according to the invention was destroyed in two runs, one with a concentration of BPC's of 5% by weight (50,000 ppm) and the other with a concentration of BPC's of 10% by weight (100,000 ppm).

The values of the process parameters were as follows: Unit Corrida 1 Corrida 2 Corrida Concentration of PCBs 0% 5% 10% Hydrocarbon: (Kg / Hr) 56.9 58.2 60.6 Oxygen: (MCN / Hr) 62.8 61.5 62.8 Steam of water: (MCN / Hr) 74.8 73.4 77.0 Temperature: ° C 1241 1268 1298 Pressure: Kg / cm2 man. 3 3 3 The hydrocarbons were treated according to the invention to produce a reducing gas in the amount and composition, dry base, shown below: Reducing gas: (MCN / Hr) 142.6 134.8 132.2 H2:% vol. 46.65 46.09 45.60 CO:% vol. 33.44 34.19 34.56 CO2:% vol. 18.71 18.54 18.86 CH4:% vol. 0.97 0.92 0.62 N2:% vol. 0.23 0.26 0.36 Nitrogen oxides: mg / m3 2.5 2.9 4.2 SO2 mg / m3 7.5 8.7 4.4 HCI: mg / m3 < 0.58 < 0.57 < 0.29 Total PCBs mg / m3 2.23E-0 53.4E-05 8.97E Dioxins and Furans ng-EQT / m3 6.5E-06 8.1 E-06 7.1 E-C The values of some process parameters were as follows: Temperature: ° C 1241 1268 1298 Pressure: Kg / cm2 man. 3 3 3 The extremely low values of PCBs in the produced gases show that the invention is very efficient in the destruction of PCBs and that the reducing atmosphere created by the partial combustion and intimate mixing of the reagents does not favor the formation of dioxins nor furans.

The cooling water used to cool and wash the reducing gases in the cooler 40 was analyzed and gave the following results: Concentration of PCBs 0% 5% 10% Chlorides in feed water: mg / l 58 Chlorides in coolant inlet mg / l 66 651 1864 Chlorides in coolant outlet mg / l 74 756 1850 BPC's in cooler outlet mg / l < 0.002 0.002 O.002 Dioxins + Furans chilled output ng / l 9.4E-05 1.5E-04 8.4E-03 The following table compares the efficiency and emission levels of the process of the invention with the levels of contaminants allowed in accordance with US regulations: Parameter Unit 0% 5% 10% EU Reg.

Efficiency% - 99.9999998 99.99999972 99.9999 (min.) Of destruction of PCBs Dioxins and Furans ngEqt m3 6.505E-06 8.100E-06 7.072E-06 0.5 Suspended particles mg / m3 6.3 2.1 2.7 30 S02 mg / m3 5.04 5.81 2.93 80 Oxides of Nitrogen mg / m3 1.67 1.94 2.81 300 Hydrogen chloride mg / m3 < 0.039 < 0.038 < 0.019 15 Various modifications and variants of the compositions, materials and methods of the invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with some specific preferred embodiments, it should be understood that the claimed invention can not be unduly limited to such specific embodiments. In fact, the intention is that various modifications of the modes described for carrying out the invention, which are obvious to those skilled in the art or related fields, are within the scope of the following claims.

Claims (13)

1. CLAIMS: 1. A method for the destruction of a toxic material comprised in a liquid hydrocarbon without producing noxious intermediates, comprising the steps of: mixing said liquid hydrocarbon comprising the toxic material with water vapor and a gas containing molecular oxygen in a flow channel and regulate the flow rates of said liquid hydrocarbon and said gases of water vapor and oxygen so that the speed of the mixture of liquid and gas at the outlet of said flow channel is greater than about 40 m / s; introducing said mixture of liquid and gas into a reaction vessel having a refractory lining at a temperature greater than about 650 ° C; maintaining said gases produced at high temperature comprising molecular hydrogen within the reaction vessel for at least about 2 seconds; maintaining a temperature at the outlet of the reaction vessel of greater than about 1000 ° C; and cooling and washing said produced gases with water, whereby a drafting gas containing hydrogen and carbon monoxide substantially free of said toxic material is produced as a result of the partial combustion of said liquid hydrocarbon.
2. 2. A method according to claim 1, wherein said toxic material is composed of one or more of the following substances: polychlorinated biphenyls, pesticides, chlorofluorocarbons, halogenated benzenes, halogenated phenols, halogenated alkanes, halogenated cycloalkanes, halogenated dioxins or halogenated dibenzofurans. and combinations of these.
3. 3. A method according to claim 1, wherein said liquid hydrocarbon is an oil.
4. 4. A method according to claim 1, wherein said velocity of the mixture of liquid and gas at the outlet of the flow channel is greater than about 50 m / s.
5. 5. A method according to claim 1, wherein the refractory lining of said reaction vessel is maintained at a temperature greater than about 750 ° C.
6. 6. A method according to claim 2, wherein said liquid hydrocarbon contains less than about 50% by weight of polychlorinated biphenyls.
7. 7. A method according to claim 2, wherein said liquid hydrocarbon containing polychlorinated biphenyls is mixed with hydrocarbons that do not contain polychlorinated biphenyls before introducing said contaminated hydrocarbon into said reaction vessel, in order to ensure partial autoothermic combustion of the mixture of hydrocarbons.
8. 8. A method according to claim 6, wherein said hydrocarbon mixture contains less than about 50% by weight of polychlorinated biphenyls before being introduced into said reaction vessel.
9. 9. A method according to claim 7, wherein said hydrocarbon mixture contains less than about 10% by weight of polychlorinated biphenyls before being introduced into said reaction vessel. A method according to claim 1, wherein the water used to cool said gas is mixed with an alkaline compound to neutralize the acidity derived from the absorption of chlorine by said water. 11. A method according to claim 1, wherein the water used to cool said gas is treated to concentrate and recover HCI derived from the absorption of chlorine by said water. 12. A system for the destruction of liquids containing toxic materials and producing a reducing gas containing hydrogen and carbon monoxide, wherein said system comprises: a partial combustion chamber, where said partial combustion chamber has a coating of refractory material adapted to be heated and maintained at a high temperature and where flame gases are produced, and where said chamber has an inlet and an outlet; a flow channel having a length-to-diameter ratio of at least about 4 and where a stream of oxygen, a stream of water vapor and a stream of liquid containing said toxic materials are intimately mixed.; wherein said flow channel has communication with the inlet of said combustion chamber; and means for cooling gases communicating with the outlet of said combustion chamber to rapidly cool said flame gases. 13. A system according to claim 12, wherein the length-to-diameter ratio of said flow channel is at least about 30.